The prior art is cognizant of the need to detect multiple aircraft flying in close formation. Such aircraft which fly in close formation may appear essentially as a single target to a conventional radar system. In military radars, this can result in underestimating the size of the threat. As one can ascertain, if there are multiple aircraft flying in close formation, and the radar detects this as a single aircraft, then the proper defense may not be provided. Hence, a greater risk of damage may result, especially in a military environment. One approach to addressing this problem has been to design radar systems which support wider bandwidth waveforms. Such systems result in a higher cost and in some cases longer waveform dwell times. The wider bandwidth waveforms often operate on only a limited range window. Thus, these radars use narrow band waveforms a majority of the time and switch to the wide band waveform only for dedicated track beams. Such radars are complicated and much more expensive than conventional radar systems.
Conventional radar systems often use frequency diverse waveforms. These radar systems use a waveform which basically consists of two or more frequency diverse subpulses. The subpulses are transmitted and are then processed in order to detect or identify a target. Such radar systems are operative to detect isolated targets. If there are multiple targets such as a squadron of aircraft flying in close formation, typical prior art radar systems will detect this condition as a single target and thus would not respond to or identify multiple targets.
The present method and apparatus describes a radar processing technique that can be used to detect the presence of multiple unresolved scatterers in a radar return. This technique includes the identification of aircraft flying in formation which would otherwise appear to be a single target based on prior art radar systems.